I wouldn't email reporters and say "we already got covered in X, why don't you cover us." That's sort of the opposite of what they want. Four things I would do:
1. Read hacking kickstarter -http://fourhourworkweek.com/2012/12/18/hacking-kickstarter-how-to-raise-100000-in-10-days-includes-successful-templates-e-mails-etc/
You won't have time for all of it since your campaign launched but still. Influencers, influencers, influencers.
2. Do some serious homework - figure out who cares about edtech or crowdfunding and email them with a hook. Each pitch shouldn't be the same.
3. Try to make friends with kickstarter folks - unfortunately, I hear his is much easier with Indiegogo but if you can find or through a connection know of something AND you can show our campaign is
You're in edtech, I'd use that to craft a story about helping teachers, kids, etc. I don't see tons of edtech campaigns, use that to your advantage.
4. Reach out to an advisor that is an expert in crowdfunding
or Kickstarter via FD - again, not tons of time but
All this said, i would not rely solely on press, your own network has to get things started.